Thermoplastic elastomer composition and ethylene-alpha-olefin copolymer

ABSTRACT

A thermoplastic elastomer composition comprising 5 to 95 wt % of the following (A) and 5 to 95 wt % of the following (B), wherein the flowability index I according to a test for flow properties with a capillary rheometer is 1.35 or more:  
     (A) an ethylene-α-olefin copolymer having a tensile stress M 100  measured according to JIS-K-6251 of 2.5 MPa or less,  
     (B) a polyolefin-based resin having a tensile stress M 100  measured according to JIS-K-6251 of 2.5 MPa or more.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a thermoplastic elastomercomposition, a molded article obtained by using the thermoplasticelastomer composition and an ethylene-α-olefin copolymer. Morespecifically, the present invention relates to a thermoplastic elastomercomposition which has excellent flexibility and processability,manifests no bleed of low molecular weight components, and particularlyexcellent in extrusion processability and calender processability, anextrusion molded article obtained by extrusion molding the thermoplasticelastomer composition or a calender molded article obtained by calendermolding the thermoplastic elastomer composition, and anethylene-α-olefin copolymer.

[0003] 2. Description of Related Art

[0004] Soft vinyl chloride materials having good balance betweenmechanical strength and flexibility are a material excellent inprocessability and cost performance. However, the use thereof isrestricted due to recent environmental problems. On the other hand, anethylene-α-olefin copolymer rubber can be listed as the polyolefin-basedmaterial excellent in recycling property. The ethylene-α-olefincopolymer rubber is used widely as an automobile material, constructionmaterial, wire material and polyolefin-modifying material, together withethylene-α-olefin-non-conjugated diene rubber such as EPDM and the like.In these uses, excellent processability, particularly excellent rollprocessability and excellent extrusion processability are required inaddition to excellent vulcanization property. From this standpoint, anethylene-α-olefin-non-conjugated diene rubber such as EPDM and the likehaving excellent processability by inclusion of a diene component isused more widely than ethylene-α-olefin copolymer rubber. As theconventional technology for further improving processability, there is amethod in which ethylene-α-olefin-non-conjugated diene rubber havingwider molecular weight distribution is produced by using a specialcatalyst such as a vanadate of secondary alcohol and the like asdisclosed, for example, in Japanese Patent Application Laid-Open (JP-A)No. 61-4708. Further, Japanese Patent Application Publication (JP-B) No.6-18942 discloses a rubber composition obtained by compounding avulcanized rubber compounding agent intoethylene-α-olefin-non-conjugated diene copolymer rubber having widemolecular weight distribution. The rubber containing a diene componenthas excellent processability, but may cause a problem of remaining ofodor in the final product since this rubber contains a diene monomerodor as compared with rubber containing no diene component.

[0005] Further, JP-A No. 9-241325 discloses an ethylene-α-olefincopolymer rubber which has excellent processability, heat-resistance andhigh tensile strength, causes no bleed in low molecular weight parts,and has a specific composition, molecular weight and molecular weightdistribution. However, in view of recent further strict qualityrequirements, this method include problems that prevention of bleed isinsufficient, the surface appearance of the final product using theabove-mentioned copolymer is degraded, further, pellets of the copolymeradhere each other under a slight load and small block form can not bemaintained for a long period of time, workability and handling such astransportation and measurement in compounding into a polyolefin-basedresin are insufficient.

SUMMARY OF THE INVENTION

[0006] The present inventors have intensively studied a thermoplasticelastomer composition having no above-mentioned problems, and found thata thermoplastic elastomer composition comprising a specificethylene-α-olefin copolymer and a specific polyolefin-based resin isexcellent in extrusion processability and calender processability, andgives excellent flexibility and processability, and manifests no bleedof low molecular weight components when made into an extrusion moldedarticle or calender-molded article, and have completed the presentinvention.

[0007] Namely, the present invention relates to a thermoplasticelastomer composition comprising 5 to 95 wt % of the following (A) and 5to 95 wt % of the following (B), wherein the flowability index Iaccording to a test for flow properties with a capillary rheometer is1.35 or more:

[0008] (A) an ethylene-α-olefin copolymer having a tensile stress M₁₀₀measured according to JIS-K-6251 of 2.5 MPa or less,

[0009] (B) a polyolefin-based resin having a tensile stress M₁₀₀measured according to JIS-K-6251 of 2.5 MPa or more.

BRIEF EXPLANATION OF THE DRAWING

[0010]FIG. 1 is a plot diagram of a ratio of shear viscosity versusshear viscosity in calculating flowability index.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described below.

[0012] The present invention relates to a thermoplastic elastomercomposition comprising 5 to 95 wt % of the following (A) and 5 to 95 wt% of the following (B), wherein the flowability index I according to atest for flow properties with a capillary rheometer is 1.35 or more:

[0013] (A) an ethylene-α-olefin copolymer having a tensile stress M₁₀₀measured according to JIS-K-6251 of 2.5 MPa or less,

[0014] (B) a polyolefin-based resin having a tensile stress M₁₀₀measured according to JIS-K-6251 of 2.5 MPa or more.

[0015] The component (A) in the present invention is anethylene-α-olefin copolymer having a tensile stress M₁₀₀ measuredaccording to JIS-K-6251 of 2.5 MPa or less. The component (A) should hasa tensile stress M₁₀₀ measured according to JIS-K-6251 of 2.5 MPa orless, preferably of 2.0 MPa or less. When this value is excess, a moldedarticle obtained by molding the resulting thermoplastic elastomercomposition is poor in flexibility.

[0016] The component (A) is preferably an ethylene-α-olefin copolymersatisfying the following conditions (a) to (c), more preferably anethylene-α-olefin copolymer additionally satisfying the followingcondition (d), further preferably an ethylene-α-olefin copolymer furtheradditionally satisfying the following conditions (e) to (g).

[0017] (a) α-olefin content is from 5 to 95 wt %,

[0018] (b) Mooney viscosity: ML₁₊₄100° C. is from 5 to 70,

[0019] (c) Q value (weight-average molecular chain length/number-averagemolecular chain length) in GPC measurement is 4 or more,

[0020] (d) a molecular weight distribution curve is bimodal,

[0021] (e) a ratio (H=X1/X2) of high molecular weight peak height X1 tolow molecular weight peak height X2 in a molecular weight distributioncurve is from 2.0 to 7.0,

[0022] (f) an area of low molecular weight parts having chain lengths of100 Å or less in a molecular weight distribution curve is 3% or less,

[0023] (g) heat of fusion of a crystal at temperature of from 50 to 100°C. is 5 mJ/mg or more when measured by a differential scanningcalorimeter (DSC).

[0024] Specific examples of the α-olefin in the component (A) includepropylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 1-hexene,1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-eicosene and the like.Among them, an α-olefin having 3 to 8 carbon atoms is preferable. Whenthe carbon number of the α-olefin is 9 or more, the monomer cost of theα-olefin becomes high, and may induce disadvantage from the viewpoint ofindustrial production. These α-olefins may be used alone or incombination thereof. The α-olefin content in the copolymer of thepresent invention is preferably from 5 to 95 wt %, more preferably from20 to 90 wt %, further preferably from 20 to 40 wt %, most preferablyfrom 25 to 40 wt %. When the α-olefin content is too low, bleed mayoccur on the surface of a molded article obtained by molding theresulting thermoplastic elastomer composition. On the other hand, whenthe α-olefin content is too high, a molded article obtained by moldingthe resulting thermoplastic elastomer composition may be poor instrength.

[0025] The Mooney viscosity: ML₁₊₄100° C. of the component (A) ispreferably from 5 to 70, more preferably from 15 to 70, and furtherpreferably from 20 to 60. When the Mooney viscosity is too low, a moldedarticle obtained by molding the resulting thermoplastic elastomercomposition may be poor in strength. On the other hand, when the Mooneyviscosity is too high, a molded article obtained by molding theresulting thermoplastic elastomer composition may has deterioratedextrusion processability.

[0026] The Q value (weight-average molecular chain length/number-averagemolecular chain length) in GPC measurement of the component (A) ispreferably 4 or more, more preferably 6 or more. When the Q value is toolow, a molded article obtained by molding the resulting thermoplasticelastomer composition may has deteriorated extrusion processability andcalender processability. Higher Q value is preferable from thestandpoints of extrusion processability and calender processability,providing the constitution conditions of the present invention aresatisfied. Measurement of the Q value is conducted by a gel permeationchromatography (GPC) method (for example, 150C/GPC apparatus,manufactured by Waters Co.). The elution temperature is 140° C., thecolumn used is, for example, Shodex Packed Column A-80M manufactured byShowa Denko K.K., and as the molecular weight reference material,polystyrene (for example, manufactured by Tosoh Corp., molecular weight;8,400,000) is used. The resulted weight-average molecular weight interms of polystyrene is represented by Mw, the resulted number-averagemolecular weight in terms of polystyrene is represented by Mn, and theratio of them (Q value=Mw/Mn) is molecular weight distribution. As themeasuring sample, about 5 mg of a polymer is dissolved in 5 ml ofo-dichlorobenzene so as to obtain a concentration of about 1 mg/ml. Theresulted sample solution (400 μl) was injected, and detection wasconducted by a refractive index detector at an elution solvent flow rateof 1.0 ml/min.

[0027] The component (A) preferably manifests a bimodal molecular weightdistribution curve. When the molecular weight distribution has singlepeak, spreading of the molecular weight distribution is insufficient,and a molded article obtained by molding the resulting thermoplasticelastomer composition may has deteriorated extrusion processability,particularly, deteriorated extruded surface, and deteriorated calenderprocessability.

[0028] The ratio (H=X1/X2) of high molecular weight peak height X1 tolow molecular weight peak height X2 in a molecular weight distributioncurve of the component (A) is preferably from 2.0 to 7.0, furtherpreferably from 2.2 to 6.0. When H is too low, bleed may occur on thesurface of a molded article obtained by molding the resultingthermoplastic elastomer composition. On the other hand, when H is toohigh, extrusion processability, particularly extruded surface maydeteriorate, and the extrusion amount may decrease.

[0029] In the molecular weight distribution curve of the component (A),the area of low molecular weight parts having chain lengths of 100 Å orless is preferably 3% or less, more preferably 2% or less. When thisarea is too large, bleed may occur on the surface of the final productof the above-mentioned copolymer or a pellet of the copolymer.

[0030] Heat of fusion of a crystal of the component at temperature offrom 50 to 100° C. is preferably 5 mJ/mg or more, more preferably 8mJ/mg or more, when measured by a differential scanning calorimeter(DSC). When this value is too small, extrusion processability,particularly shape retaining property of the copolymer may deteriorate.As the differential scanning calorimeter, there is used, for example,DSC220 manufactured by Seiko Instruments Inc., and the measurement isconducted at a rate of 10° C./min. in temperature rising process.

[0031] The component (A) can be produced by polymerizing ethylene andα-olefin using a single reactor or twin reactor in the presence of acatalyst system obtained by combining the following components (C) to(E). A three or more reactor may also be used, providing theconstitution conditions of the present invention are satisfied.

[0032] As the component (C), a vanadium compound represented by thegeneral formula VO(OR)_(n)X_(3-n) (wherein, R is a hydrocarbon group, Xis halogen, 0≦n≦3) can be used, and examples thereof include VOCl₃,VO(OCH₃)Cl₂, VO(OCH₃)₂Cl, VO(OCH₃)₃, VO(OC₂H₅)Cl₂, VO(OC₂H₅)₂Cl,VO(OC₂H₅)₃, VO(OC₃H₇)Cl₂, VO(OC₃H₇)₂Cl, VO(OC₃H₇)₃, VO(O-iso-C₃H₇)Cl₂,VO(O-iso-C₃H₇)₂Cl, VO(O-iso-C₃H₇)₃, VO(O-n-C₄H₉)Cl₂, VO(O-n-C₄H₉)₂Cl,VO(O-n-C₄H₁₉)₃ or mixtures thereof. Among them, those other than VOCl₃can be obtained easily by reacting VOCl₃ with alcohol or reacting VOCl₃with VO(OR)₃.

[0033] As the component (D), an organoaluminum compound represented bythe general formula R′_(m)AlX_(3-m) (wherein, R′ is a hydrocarbon group,X is halogen, 0≦n≦3) can be used, and examples thereof include(C₂H₅)₂AlCl, (C₄H₉)₂AlCl, (C₆H₁₃)₂AlCl, (C₂H₅)_(1.5)AlCl_(1.5),(C₄H₉)_(1.5)AlCl_(1.5), (C₆H₁₃)_(1.5)AlCl_(1.5), C₂H₅AlCl₂, C₄H₉AlCl₂,C₆H₁₃AlCl₂ and the like.

[0034] Though the copolymer of the present invention can be obtained byusing a catalyst system consisting essentially of the component (C) andthe component (D), the following component (E) may also be combined forthe purpose of further reducing the amount of low molecular weightcomponents which is a main factor of bleed.

[0035] As the component (E), a halogenated ester compound represented bythe following general formula can be used.

[0036] (wherein, R″ is an organic group having 1 to 20 carbon atoms,partially or completely substituted by halogen atoms, and R′″ is ahydrocarbon group having 1 to 20 carbon atoms.). A compound in which thesubstituent R″ is completely substituted by chlorine atoms ispreferable, and a perchlorocrotonate is further preferable. Examplesthereof include ethyldichloroacetate, methyltrichloroacetate,ethyltrichloroacetate, methyldichlorophenylacetate,ethyldichlorophenylacetate, methylperchlorocrotonate,ethylperchlorocronate, propylperchlorocrotonate,isopropylperchlorocrotonate, butylperchlorocrotonate,cyclopropylperchlorocrotonate, phenylperchlorocrotonate and the like.

[0037] It is preferable that the molar ratio of the organoaluminumcompound (D) to the vanadium compound (C) is 2.5 or more and the molarratio of the halogenated ester compound (E) to the vanadium compound (C)is 1.5 or more, in the polymerization reaction.

[0038] The component (A) in the present invention can be produced byusing one or more of known Ziegler-Natta catalysts or known single sitecatalysts and using a single reactor or two or more reactor. A knownsingle site catalyst is preferable from the standpoint of the uniformityof the composition distribution of the resulting polymer, and examplesof such a single site catalyst include, for example, metallocene-basedcatalysts described in JP-A Nos. 58-19309, 60-35005, 60-35006, 60-35007,60-35008, 61-130314, 3-163088, 4-268307, 9-12790, 9-87313, 10-508055,11-80233, Japanese Patent Kohyo Publication No. 10-508055 and the like,non-metallocene-based complex catalysts described in JP-A Nos.10-316710, 11-100394, 11-80228, 11-80227, Japanese Patent KohyoPublication No. 10-513489, JP-A Nos. 10-338706 and 11-71420. Among them,a metallocene-based catalysts are generally used. As the suitablematallocene catalyst of them, a complex of a III to XII transition metalin periodic table which has at least one cyclopentadiene type anionskeleton and has a C₁ symmetrical structure is preferable from thestandpoint of the flexibility of the resulting polymer. Further, as theexample of a suitable production method using a metallocene catalyst inobtaining a polymer having high molecular weight, a method isexemplified in which ethylene and α-olefin are copolymerized in thepresence of an olefin polymerization catalyst comprising the following(α), (β) and/or (γ).

[0039] (α): at least one of transition metal complexes represented bythe following general formulae [I] to [III],

[0040] (in each of the above-described general formulae [I] to [III], M¹represents a IV group transition metal atom in periodic table ofelement, A represents a XVI group atom in periodic table of element, andJ represents a XIV group atom in periodic table of element. Cp¹represents a group having a cyclopentadiene type anion skeleton. Each ofX¹, X², R¹, R², R³, R⁴, R⁵ and R⁶ independently represents a hydrogenatom, halogen atom, alkyl group, aralkyl group, aryl group, substitutedsilyl group, alkoxy group, aralkyloxy group, aryloxy group ordisubstituted amino group. X³ represents a XVI group atom in periodictable of element. R¹, R², R³, R⁴, R⁵ and R⁶ may optionally bond to forma ring. Two of M¹, A, J, Cp¹, X¹, X², X³, R¹, R², R³, R⁴, R⁵ and R⁶ maybe the same or different, respectively.).

[0041] (β): One or more aluminum compounds selected from the following(β1) to (β3):

[0042] (β1): Organoaluminum compound represented by the general formulaE¹ _(a)AlZ_(3-a),

[0043] (β2): Aluminoxane having a structure represented by the generalformula {—Al(E²)—O—}_(b),

[0044] (β3): Aluminoxane having a structure represented by the generalformula E³{—Al(E³)—O—}_(c)AlE³ ₂:

[0045] (wherein, E¹, E² and E³ represent hydrocarbon groupsrespectively, and all of E¹, all of E² and all of E³ may be the same ordifferent. Z represents a hydrogen atom or halogen atom, and all of Zmay be the same or different. “a” represents a number satisfying 0<a≦3,“b” represents an integer of 2 or more and “c” represents an integer of1 or more.).

[0046] (γ) Boron compound of any of the following (γ1) to (γ3).

[0047] (γ1): Boron compound represented by the general formula BQ¹Q²Q³.

[0048] (γ2): Boron compound represented by the general formulaG+(BQ¹Q²Q³Q⁴).

[0049] (γ3): Boron compound represented by the general formula(L-H)+(BQ¹Q²Q³Q⁴).

[0050] (wherein, B is a boron atom in atomic trivalent, Q¹ to Q⁴ may bethe same or different and represent a halogen atom, hydrocarbon group,halogenated hydrocarbon group, substituted silyl group, alkoxy group ordisubstituted amino group. G⁺ is an inorganic or organic cation, L is aneutral Lewis acid, and (L-H)⁺ is a Broensted acid.).

[0051] Specific examples of the inactive hydrocarbon medium used inpreparing a catalyst include aliphatic hydrocarbons such as propane,butane, pentane, hexane, heptane, octane, decane, dodecane, kerosene andthe like, alicyclic hydrocarbons such as cyclopentane, cyclohexane,methylcyclopentane and the like, aromatic hydrocarbons such as benzene,toluene, xylene and the like, halogenated hydrocarbons such as ethylenechloride, chlorobenzene, dichloromethane and the like, or mixturesthereof. The preparation temperature is preferably in the range of from−100° C. to 250° C., and pressure and time can be set in any ranges.

[0052] Polymerization of the component (A) is conducted in a hydrocarbonsolvent. Examples of the hydrocarbon solvent include aliphatichydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane,kerosene and the like, alicyclic hydrocarbons such as cyclohexane,methylcyclopentane, methylcyclohexane and the like, and aromatichydrocarbons such as benzene, toluene, xylene and the like. Also,α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene and the likecan be used as a part of all of the solvent. The polymerizationtemperature is preferably from 40 to 160° C., and further preferablyfrom 40 to 80° C. from the standpoints of productivity and control ofmolecular weight.

[0053] The polymerization is conducted under pressure or atmosphericpressure using a single reactor or a two reactor in line, and preferablycarried out at 0.1 to 5 MPa, particularly preferably at 0.1 to 2 MPa.The average retention time of the reaction liquid per one polymerizationbath is preferably from 2 to 180 minutes, further preferably from 20 to120 minutes, and the polymer concentration is preferably 15 wt % orless, further preferably 12 wt % or less from the standpoint ofreduction of the viscosity of the reaction liquid.

[0054] As a material used to control the molecular weight of thecomponent (A), hydrogen, diethylamine, arylchloride pyridine-N-oxide andthe like are exemplified, and hydrogen is particularly preferable.

[0055] When two reactors are used, the temperatures of the first reactorand the second reactor can be set arbitrary and the molecular weightcontrolling agent can be arbitrary set, and it is preferable that apolymer having high molecular weight is produced in the first reactorand a polymer having low molecular weight is produced in the secondreactor, and it is preferable that the polymerization temperature of thefirst reactor is from 40 to 60° C., and the polymerization temperatureof the second reactor is from 50 to 80° C. When the polymerizationtemperature of the first reactor is too high, the molecular weight of apolymer having high molecular weight may become insufficient. When thepolymerization temperature of the second reactor is too low, it may benecessary to use a molecular weight controlling agent in large amount.

[0056] On the other hand, the molecular weight controlling agent can beadded to either the first reactor or the second reactor or to both ofthem. If the use amount in the first reactor is decreased and the useamount in the second reactor is increased, it is preferable thatsufficient amount of high molecular weight polymer and low molecularweight polymer can be polymerized.

[0057] The ratio of the production amounts of copolymers in the firstreactor to the second reactor is preferably within the range from2.0/0.05 to 1/2.5. Further, a more preferable result is obtained whenthe copolymerization is conducted in the range from 2.0/0.1 to 2/1.5.

[0058] The component (A) can be obtained by blending two or more kindsof polymers.

[0059] Herein, a polymer having high molecular weight and a polymerhaving low molecular weight can be polymerized and blendedsimultaneously by use of a catalyst system of the known Ziegler-Nattacatalyst or by co-use of known single site catalysts described above,and this is a method also suitable for mass production. In this case, aplurality of polymerization reactor are not necessarily required, andonly one reactor may be used without problem.

[0060] When the component (A) is used as a polyolefin-based resinmodifier, it is preferably made into a pellet.

[0061] As the form of this pellet, sphere, cylinder, lens and cube areexemplified. These can be produced by a known pellet forming method, andfor example, when the component (A) is melt-mixed and extruded throughan extruder and subjected to hot cut or strand cut, a pellet in the formof sphere, cylinder or lens is obtained. In this case, cut may beconducted in any flow such as water flow, air flow and the like. Apellet in the form of cube is obtained by mixing the raw materialuniformly, then, molding it into a sheet by a roll and the like, andsubjected the molded one to a sheet pelletizer. Regarding the size, thelongest part of a pellet is preferably 3 cm or less. In the case of apellet having larger size than 3 cm, measuring error may increase.

[0062] A pellet of the component (A) is preferably dusted with one ormore of calcium stearate, calcium carbonate, barium sulfate, silica,talc, stearic acid and polyolefin powder, from the standpoints offurther suppression of mutual adhesion, or suppression of bridgingphenomenon of a pellet in removing out of a silo and the like. Thedusting amount may be controlled depending on the size and form of apellet according to demand. In general, it is preferably added in anamount of 0.05 to 3 parts by weight based on the pellet. When theaddition amount is too low, the effect for further suppressing mutualadhesion may not be manifested. When the addition amount is too high, itmay be a cause for decrease in physical property and the like andincrease in production cost. In particular, when the transparency of thefinal product is important, a polyolefin powder is preferably used. Asthe polyolefin powder, polyethylene-based resins and polypropylene-basedresins are listed.

[0063] The average particle size of a polyolefin powder is preferably500 μm or less, particularly preferably 300 μm or less. When theparticle size is larger, adhesion on the surface of a pellet may not beoccurred and the mutual adhesion property-improving effect may not beobtained.

[0064] The component (B) in the present invention is a polyolefin-basedresin having a tensile stress M₁₀₀ measured according to JIS-K-6251 of2.5 MPa or more. The component (B) should has a tensile stress M₁₀₀measured according to JIS-K-6251 of 2.5 MPa or more, preferably 3.0 MPaor more. When this value is too low, a molded article obtained bymolding the resulting thermoplastic elastomer composition may be poor instrength

[0065] Examples of the component (B) include polyethylene-based resinssuch as high density polyethylene, middle density polyethylene, lowdensity polyethylene, LLDPE (linear low density polyethylene);polypropylene-based resins, polybutene-based resins,poly-4-methyl-pentene-1, ethylene-vinyl acetate copolymer resin,ethylene-methyl methacrylate copolymer resin, ethylene-methacrylatecopolymer resin, ethylene-acrylate copolymer resin, ethylene-methacrylicacid copolyemr resin, ethylene-acrylic acid copolymer resin,ethylene-styrene copolymer resin and the like. Further, two or morecomponents (B) may also be co-used.

[0066] The Q value (weight-average molecular chain length/number-averagemolecular chain length) of the component (B) in GPC measurement ispreferably 3 or more, more preferably 3.5 or more, from the standpointof improvement of the extrusion processability of a molded articleobtained by molding the resulting thermoplastic elastomer composition.For measuring the Q value, the method described in the column of thecomponent (A) may advantageously be used.

[0067] The thermoplastic elastomer composition of the present inventioncomprises 5 to 95 wt % of the component (A) and 5 to 95 wt % of thecomponent (B), preferably comprises 10 to 90 wt % of the component (A)and 10 to 90 wt % of the component (B), more preferably comprises 20 to80 wt % of the component (A) and 20 to 80 wt % of the component (B).When the amount of the component (A) is too low (that is, the amount ofthe component (B) is too high), a molded article obtained by molding theresulting thermoplastic elastomer composition is poor in flexibility andextrusion processability, particularly, shape retaining property, whilewhen the amount of the component (A) is too high (that is, the amount ofthe component (B) is too low), a molded article obtained by molding theresulting thermoplastic elastomer composition is poor in strength.

[0068] The thermoplastic elastomer composition of the present inventionshould has a flowability index I according to a test for flow propertieswith a capillary rheometer of 1.35 or more, preferably of 1.40 or more,more preferably of 1.50 or more. When this index is too low, thenon-Newtonian property of melt flowability is insufficient, and asufficient effect for improving extrusion processability is notobtained. Higher flowability index is preferable from the standpoint ofextrusion processability, providing the constitution conditions of thepresent invention are satisfied.

[0069] A test for flow properties with a capillary rheometer andcalculation of flowability index are conducted according to thefollowing methods.

[0070] Measuring apparatus: Capirograph 1C, manufactured by Toyo SeikiSeisaku-Sho, Ltd.

[0071] Die: capillary diameter of 1 mm, capillary length of 10 mm

[0072] Temperature: 190° C.

[0073] Shear rate: 12, 37, 61, 122, 365, 608 (s⁻¹)

[0074] The shear viscosity was measured at each shear rate.

[0075] The flowability index, I=A/B, was calculated from the shearviscosity ratio (shear viscosity at a shear rate of 12 (s⁻¹)/shearviscosity at a shear rate of 365 (s⁻¹)) and plot (see, FIG. 1) of theshear viscosity at a shear rate of 12 (s⁻¹) The solid line in the figureis a master curve of EPM which has a Q value by GPC measurement of 1.8and has no long chain branching, and represented by the formulaY-0.5917×10⁻³X+1.2640. When the plot of a thermoplastic elastomercomposition shifts toward positive direction of Y axis (shear viscosityratio), the non-Newtonian property of the composition is higher, and itis related to extrusion processability, for example, melt flowphenomenon of extruded surface and the like.

[0076] In the present invention, there may be appropriately compounded,as the additional component, additives such as an antioxidant,antistatic agent, anti-weathering agent, ultraviolet absorber, strippingagent, dispersing agent and the like, coloring agents such as carbonblack and the like, fillers such as glass fiber, carbon fiber, metalfiber, aramide fiber, glass bead, asbestos, mica, calcium carbonate,potassium titanate whisker, talc, barium sulfate, glass flake and thelike, or other rubber-like polymers or thermoplastic resins and thelike, in addition to the above-mentioned components.

[0077] The thermoplastic elastomer composition of the present inventioncan also be subjected to cross-linking such as sulfur cross-linking,peroxide cross-linking, metal ion cross-linking, silane cross-linking,water cross-linking and the like, by conventionally known methods, ifnecessary.

[0078] For obtaining the thermoplastic elastomer composition of thepresent invention, the components (A) and (B) and additional componentsappropriately used may advantageously be kneaded by a usual kneadingmachine, for example, a rubber mill, brabender mill, Banbury mixer,pressure kneading, twin screw extruder and the like. The kneadingmachine may be any of closed type machine or open type machine, and aclosed type machine which can be substituted with an inert gas ispreferable. The kneading temperature is a temperature at which all ofthe mixed components are melted, and usually from 160 to 250° C.,preferably from 180 to 240° C. The kneading time is usually from about 3to 10 minutes when a kneading machine such as a pressure kneader,Banbury mixer and the like is used, though the kneading time is notdetermined since it depends on the kind and amount of the componentmixed and the kind of the kneading machine. In the kneading process,components may be kneaded at one time, alternatively, there may also beadopted a multi-step division kneading method in which a part ofconstituents components are kneaded, and then the remaining componentsare added and the kneading is continued.

[0079] The thermoplastic elastomer composition and ethylene-α-olefincopolymer of the present invention are excellent particularly as amaterial for extrusion molding, and can be melt-extruded through anextruder equipped with a mold in the form of the molded article, at thetip of the extruder, and cooled and cut to obtain a heteromorphicextrusion-molded article.

[0080] Further, the thermoplastic elastomer composition andethylene-α-olefin copolymer of the present invention are excellentparticularly as a material of calender molding, and a calender moldedarticle can be obtained by a sheeting process in which a smooth sheethaving higher thickness accuracy is produced continuously, a doublingprocess in which a sheet having higher thickness accuracy containing nopin hole is produced continuously in laminating the same or differentthermoplastic elastomer compositions and thermoplastic resincompositions, a topping process in which a composite is continuouslyproduced by laminating cloth and the like onto a sheet, a frictionprocess in which a thermoplastic elastomer composition is imprinted intocloth for the purpose of improving adhesion, or a profiling process inwhich a carved pattern is made on the surface of a roll and this patternis transcribed continuously onto the surface of a sheet.

[0081] The thermoplastic elastomer composition and ethylene-α-olefincopolymer of the present invention can be used in parts such as apacking, housing and the like of automobile interior or exterior partsand weak electric parts, industrial parts, water-proof parts and thelike, in stead of the conventional soft vinyl chloride-based resins.Among them, due to flexibility, excellent extrusion processability,further, the absence of bleed, they can be used in a hose, tube, gasketand packing. Regarding use examples thereof, as the hose and tube use,there are listed an air hose, water hose, reinforcing agent-containingair hose, reinforcing agent-containing water hose and medical tube, asthe gasket use, there are listed an aluminum sash sealing gasket andgasket around doors of an automobile, and as the packing use, there islisted a packing of a refrigerator door.

EXAMPLES

[0082] The following examples further illustrate the present inventionspecifically, but do not limit the scope of the present invention. Inthe present invention, the term excellent extrusion processability meansthat the surface skin of the extrusion-molded article is smooth and theappearance of the resulting final product does not deteriorate. In thepresent invention, the term excellent calender processability means thatsheet removal from the roll surface can be conducted easily.

[0083] [I] Production and Evaluation of Copolymer

[0084] Measurements were conducted as described below.

[0085] (1) Measurement by Differential Scanning Calorimeter (DSC)

[0086] Measurements were conduced at a rate of 10° C./min. in any oftemperature rising process and constant temperature process, using adifferential scanning calorimeter (DSC220C, manufactured by SeikoInstruments Inc.).

[0087] (2) Measurement by GPC

[0088] The GPC measurement was conducted at an elution temperature of140° C. using 150C manufactured by Waters, Shodex Packed ColumnA-80 M(manufactured by Showa Denko K.K.) as a column, and polystyrene(manufactured by Tosoh Corp., molecular weight; 68-8,400,000) as amolecular weight reference material. The resulted weight-averagemolecular weight in terms of polystyrene was represented by Mw, theresulted number-average molecular weight in terms of polystyrene wasrepresented by Mn, and the ratio of them (Q value) was molecular weightdistribution, and the higher molecular weight peak height (X1), lowermolecular weight peak height (X2) in a molecular weight distributioncurve and the ratio (H=X1/X2) of them were measured. For preparing ameasuring sample, about 5 mg of a polymer was dissolved in 5 ml ofo-dichlorobenzene so as to obtain a concentration of about 1 mg/ml. Theresulted sample solution (400 μl) was injected, and detection wasconducted by a refractive index detector at an elution solvent flow rateof 1.0 ml/min.

[0089] (3) Flexibility

[0090] The hardness of a copolymer was measured according to JIS-K-6253.

[0091] (4) Tensile Stress

[0092] A copolymer was press-molded at 150° C. to obtain a sheet of 2 mmthickness, then, the tensile stress M₁₀₀ of the copolymer was measuredaccording to JIS-K-6251. A specimen was made by using No. 3 dumbbell.

[0093] (5) Preparation and Evaluation of Copolymer Pellet

[0094] A copolymer was heated for 30 minutes in a Geer oven at 100° C.,then, a sheet of 4 mm thickness was molded by 10 inch open rolls. Thissheet was ground by a sheet pelletizer to obtain a pellet in the form ofcube. This pellet was dusted with 0.18 g of calcium stearate and 0.18 gof Irganox 1076 (antioxidant, manufactured by Chiba Specialty Chemicals)per 150 g of the pellet, and this was filled in a glass beaker(diameter: 8.6 cm), charged with a load of 1900 g, left for 14 hoursunder atmosphere of 40° C., then, the mutual adhesion of the pellet wasevaluated.

[0095] Judge of Mutual Adhesion of Pellet

[0096] 1: The form of a pellet is completely kept, and no adhesion isfound between pellets at all.

[0097] 2: Though the form of a pellet is kept, and adhesion is foundbetween pellets.

[0098] 3: The form of a pellet is not kept, and adhesion is foundbetween pellets.

[0099] (6) Evaluation of Bleeding Property

[0100] A copolymer was press-molded at 15° C. to obtain a sheet of 2 mmthickness, then, left for 48 hours, and the bleeding property of thesurface of the sheet was evaluated.

[0101] Judge of Bleeding Property

[0102] ◯: The surface of a sheet is clean, and no stickiness is found byfinger touch.

[0103] Δ: The surface of a sheet is somewhat cloudy, and stickiness isfound by finger touch.

[0104] X: An oil film is observed on the surface of a sheet.

[0105] (7) Evaluation of Extrusion Processability

[0106] The pellet obtained in the method of (5) was extrusion-moldedusing a 40 mm φ single screw extruder (full flight screw L/D28) througha flat die of 70 mm width, and the extruded surface and appearance ofthe resulted molded article were observed.

[0107] Judge of Extruded Surface

[0108] ◯: Extruded surface is smooth.

[0109] X: Extruded surface is not smooth, but rough.

[0110] Judge of Appearance

[0111] ◯: Extrusion-molded article keeps edge in the form of a die evenafter molding.

[0112] X: Molded article causes disintegration after extrusion-molding,and edge in the form of a die is not kept.

Example 1 Synthesis of component (A)-1

[0113] Into the lower portion of a 100 L reactor made of stainless steelequipped with a stirrer were continuously fed 62.8 kg of hexane as apolymerization solvent and ethylene and propylene at rates of 5.90 kgand 22.44 kg per hour, respectively. VO(O-iso-C₃H₇)₃ and ethylaluminumsesquichloride (EASC) were fed continuously as a catalyst, at ratios of2.22 g and 7.79 g per hour, respectively, and the temperature of thepolymerization chamber was kept at 50° C. A part of the polymerizationliquid in the first reactor was extracted, and a polymer was allowed todeposit and dried by steam stripping. A copolymer was thus obtained at arate of 4.6 kg per hour. The control of the molecular weight wasconducted by using hydrogen. The results are shown in Table 1.

Example 2 Synthesis of component (A)-2

[0114] According to the same manner as in Example 1, hexane was fed at arate of 62.8 kg per hour and ethylene and propylene were fed at rates of5.44 kg and 23.39 kg per hour, respectively, continuously.VO(O-iso-C₃H₇)₃ and ethylaluminum sesquichloride (EASC) were fedcontinuously as a catalyst, at ratios of 0.70 g and 2.49 g per hour,respectively, and the temperature of the polymerization chamber was keptat 50° C. A part of the polymerization liquid in the first reactor wasextracted, and a polymer was allowed to deposit and dried by steamstripping. A copolymer was thus obtained at a rate of 2.6 kg per hour.The control of the molecular weight was conducted by using hydrogen. Theresults are shown in Table 1.

Example 3 Synthesis of component (A)-3

[0115] According to the same manner as in Example 1, hexane was fed at arate of 62.8 kg per hour and ethylene and propylene were fed at rates of5.44 kg and 25.78 kg per hour, respectively, continuously.VO(O-iso-C₃H₇)₃ and ethylaluminum sesquichloride (EASC) were fedcontinuously as a catalyst, at ratios of 0.64 g and 2.24 g per hour,respectively, and the temperature of the polymerization chamber was keptat 50%. A part of the polymerization liquid in the first reactor wasextracted, and a polymer was allowed to deposit and dried by steamstripping. A copolymer was thus obtained at a rate of 2.0 kg per hour.The control of the molecular weight was conducted by using hydrogen. Theresults are shown in Table 1.

Example 4 (Synthesis of component (A)-4

[0116] According to the same manner as in Example 1, hexane was fed at arate of 62.8 kg per hour and ethylene and propylene were fed at rates of5.44 kg and 23.39 kg per hour, respectively, continuously.VO(O-iso-C₃H₇)₃ and ethylaluminum sesquichloride (EASC) were fedcontinuously as a catalyst, at ratios of 0.78 g and 2.72 g per hour,respectively, and the temperature of the polymerization chamber was keptat 50° C. A part of the polymerization liquid in the first reactor wasextracted, and a polymer was allowed to deposit and dried by steamstripping. A copolymer was thus obtained at a rate of 2.2 kg per hour.The control of the molecular weight was conducted by using hydrogen. Theresults are shown in Table 3.

Comparative Example 1

[0117] According to the same manner as in Example 1, hexane was fed at arate of 6-2.8 kg per hour and ethylene and propylene were fed at ratesof 5.44 kg and 23.39 kg per hour, respectively, continuously.Additionally, 5-ethylidene-2-norbornene as the third component was fedat a rate of 0.81 kg per hour. VO(O-iso-C₃H₇)₃ and ethylaluminumsesquichloride (EASC) were fed continuously as a catalyst, at ratios of6.95 g and 24.33 g per hour, respectively, and the temperature of thepolymerization chamber was kept at 50° C. A part of the polymerizationliquid in the first reactor was extracted, and a polymer was allowed todeposit and dried by steam stripping. A copolymer was thus obtained at arate of 4.9 kg per hour. The control of the molecular weight wasconducted by using hydrogen. The results are shown in Table 2.

Comparative Example 2

[0118] According to the same manner as in Example 1, hexane was fed at arate of 120.3 kg per hour and ethylene and propylene were fed at ratesof 4.34 kg and 8.69 kg per hour, respectively, continuously.VO(O-iso-C₃H₇)₃ and ethylaluminum sesquichloride (EASC) were fedcontinuously as a catalyst, at ratios of 2.27 g and 4.77 g per hour,respectively, and the temperature of the polymerization chamber was keptat 55° C. A part of the polymerization liquid in the first reactor wasextracted, and a polymer was allowed to deposit and dried by steamstripping. A copolymer was thus obtained at a rate of 4.0 kg per hour.The control of the molecular weight was conducted by using hydrogen. Theresults are shown in Table 2.

Comparative Example 3

[0119] According to the same manner as in Example 1, hexane was fed at arate of 108.4 kg per hour and ethylene and propylene were fed at ratesof 6.45 kg and 15.1 kg per hour, respectively, continuously. VOCl₃,ethanol and ethylaluminum sesquichloride (EASC) were fed continuously asa catalyst, at ratios of 2.9 g, 1.4 g and 17.1 g per hour, respectively,and the temperature of the polymerization chamber was kept at 52° C. Apart of the polymerization liquid in the first reactor was extracted,and a polymer was allowed to deposit and dried by steam stripping. Acopolymer was thus obtained at a rate of 6.5 kg per hour. The control ofthe molecular weight was conducted by using hydrogen. The results areshown in Table 3.

[0120] The results in Tables 1 to 3 teach the following matters. Theethylene-propylene copolymers of Examples 1 to 4 satisfying theconditions of the present invention do not cause bleeding of lowermolecular weight components, and manifest excellent flexibility,extrusion processability, and handling property of a pellet.

[0121] [II] Production and Evaluation of Thermoplastic ElastomerComposition

[0122] The compositions shown in Tables 4 to 8 were kneaded for 5minutes at a temperature of 130° C. and a screw revolution of 100 rpmusing a Plasti-Corder with a roller mixer (manufactured by BrabenderOHG). The compositions were press-molded at 150° C., and subjected tothe following tests. They were evaluated in the same manner except thatthe kneading temperature was 200° C. and the press-molding temperaturewas 200° C. in Brabender Plasti-Corder in example 8 and ComparativeExample 3,

[0123] Tensile test: The tensile stress (M₁₀₀), tensile strength atbreak (TB) and elongation at break (EB) were measured according toJIS-K-6251.

[0124] Hardness: The hardness by Duro type A hardener was measuredaccording to JIS-K-6253.

[0125] Flowability: The melt flow rate at 190° C. or 230° C. wasmeasured according to JIS-K-7210.

[0126] A test for flow properties with a capillary rheometer andcalculation of flowability index: Each Shear viscosity was measuredusing Capirograph 1C (manufactured by Toyo Seiki Seisaku-Sho, Ltd.) at afurnace body temperature of 190° C., a capillary diameter of 1 mm and acapillary length of 10 mm, at a shear rate of 12, 37, 61, 122, 365, 608(s⁻¹).

[0127] The flowability index was calculated from the shear viscosityratio (shear viscosity at a shear rate of 12 (s⁻¹)/shear viscosity at ashear rate of 365 (s⁻¹)) and plot (see, FIG. 1) of the shear viscosityat a shear rate of 12 (s⁻¹), providing the flowability index I=A/B.

[0128] Extrusion processability: A thermoplastic elastomer compositionwas allowed to flow under condition of a shear rate of 122 (s⁻¹)) in theabove-described test for flow properties with a capillary rheometer, andthe extruded surface of the composition was observed.

[0129] Judge of Extrusion Processability

[0130] ◯: Extruded surface is smooth.

[0131] Δ: Extruded surface reveals slight roughness.

[0132] X: Extruded surface is not smooth, but rough.

[0133] Bleeding Property:

[0134] Evaluation of Bleeding Property

[0135] A copolymer was press-molded at 150° C. or 200° C. to obtain asheet of 2 mm thickness, then, left for 48 hours, and the bleedingproperty of the surface of the sheet was evaluated.

[0136] Judge of Bleeding Property

[0137] ◯: The surface of a sheet is clean, and no stickiness is found byfinger touch.

[0138] Δ: The surface of a sheet is somewhat cloudy, and stickiness isfound by finger touch.

[0139] X: An oil film is observed on the surface of a sheet.

Examples 5 to 13, 15 to 17 and Comparative Examples 4 to 8, 10 to 12

[0140] The results in Tables 4 to 8 teach the following matters. Thethermoplastic elastomer compositions obtained by using theethylene-propylene copolymer, component (A)-1 satisfying the conditionsof the present invention are excellent in flexibility and extrusionprocessability.

Example 14 and Comparative Example 9

[0141] The compositions shown in Table 9 were melt-kneaded for 10minutes at a rotor revolution of 50 rpm using a 16 L sealed type mixer.Then, a sheet of 4 mm thickness was molded by 8 inch open rolls, and wasground by a sheet pelletizer to obtain a pellet in the form of cube.This pellet was dusted with 0.12 g of calcium stearate and 0.12 g ofIrganox 1076 (antioxidant, manufactured by Chiba Specialty Chemicals)per 100 g of the pellet, then, this was processed into a tube having anouter diameter of 12 mm and a thickness of 1.5 mm, using a 50 mm φsingle screw extruder (screw L/D=24), at a screw revolution of 30 rpm, adie temperature of 160° C., an adapter temperature of 160° C. and acylinder temperatures from 130 to 160° C., a drawing rate of 3.5 m/min.,and the extruded surface of the resulted tube was observed.

[0142] Judge of Extrusion Processability

[0143] ◯: Extruded surface is smooth.

[0144] X: Extruded surface is not smooth, but rough. TABLE 1 Example 1Example 2 Example 3 Ethylene content wt % 73.1 76.3 66.3 Propylenecontent wt % 26.9 23.7 33.7 END content wt % 0 0 0 ML₁₊₄100° C. 42.340.4 55.3 GPC measurement result Q Mw/Mn 7.7 9.0 10.1 Mn  4.1 × 10⁴  3.5× 10⁴  4.1 × 10⁴ Mw 31.8 × 10⁴ 31.4 × 10⁴ 41.4 × 10⁴ H X1/X2 2.4 2.0 2.6Molecular weight Bimodal Bimodal Bimodal distribution form Area of lowermolecular % 1.0 0.6 0.4 weight parts having chain lengths of 100 Å orless DSC measurement result Fusion heat of crystal mJ/mg 9.2 17.5 11.7in the range from 50 to 100° C. M₁₀₀ MPa 1.3 1.8 1.3 Hardness (Duro A)57 68 59 Mutual adhesion of 1 1 1 pellet Bleeding property ∘ Δ ∘

[0145] TABLE 2 Comparative Comparative example 1 example 2 Ethylenecontent wt % 61.9 80.2 Propylene content wt % 30.8 19.8 ENB content wt %7.3 0 ML₁₊₄100° C. 30.0 36.0 GPC measurement result Q Mw/Mn 8.0 4.5 Mn 2.8 × 10⁴  5.0 × 10⁴ Mw 22.6 × 10⁴ 22.5 × 10⁴ H X1/X2 1.6 Molecularweight distribution form Bimodal Bimodal Area of lower molecular % 1.30.5 weight parts having chain lengths of 100 Å or less Fusion heat ofcrystal in the mJ/mg 1.5 range from 50 to 100° C. M₁₀₀ MPa 0.8 1.9Hardness (Duro A) 43 70 Mutual adhesion of pellet 2 2 Bleeding property∘ x

[0146] TABLE 3 Comparative Example 4 example 3 Ethylene content wt %71.0 73.0 Propylene content wt % 29.0 27.0 ML₁₊₄100° C. 40 52 GPCmeasurement result Q Mw/Mn 10.3 1.8 Mn  3.3 × 10⁴ 16.2 × 10⁴ Mw 34.5 ×10⁴ 29.6 × 10⁴ H X1/X2 2.0 Molecular weight Bimodal Monomodaldistribution form Area of lower molecular % 0.6 0.0 weight parts havingchain lengths of 100 Å or less DSC measurement result Fusion heat ofcrystal in the mJ/mg 12.1 0.7 range from 50 to 100° C. M₁₀₀ MPa 1.3 1.4Extrusion processing condition Screw revolution rpm 40 45 Dietemperature ° C. 200 180 Cylinder temperature ° C. 50˜130 110˜180Extruded surface ∘ x Appearance ∘ x

[0147] TABLE 4 Exam- Exam- Example Example ple ple Unit 5 6 7 8 (A)-1 wt% 70 60 50 30 (B)-1 wt % 30 40 50 70 Antioxidant wt % 0.12 0.12 0.120.12 M100 MPa 1.8 2.1 2.4 2.9 TB MPa 2.7 4.6 6.4 7.0 EB % 740 930 870840 Hardness Duro A 68 70 75 79 MFR190° C. g/10 1.0 1.2 2.4 3.8 minuteFlowability index I A/B 1.70 1.96 2.21 2.77 Extrusion ∘ ∘ ∘ ∘processability Bleeding property ∘ ∘ ∘ ∘

[0148] TABLE 5 Example Unit 9 Example 10 Example 11 (A)-1 wt % 70 60 50(B)-2 wt % 30 40 50 Antioxidant wt % 0.12 0.12 0.12 M100 MPa 1.7 2.1 2.3TB MPa 2.8 7.4 11.6 EB % 740 830 810 Hardness Duro A 69 71 74 MFR190° C.g/10 0.6 0.8 1.1 Flowability index I minute 1.67 1.65 1.94 Extrusion A/B∘ ∘ ∘ processability Bleeding property ∘ ∘ ∘

[0149] TABLE 6 Example Example Example Example Example Unit 12 13 15 1617 (A)-1 wt % 70 50 49 60 80 (B)-2 wt % 20 (B)-3 wt % 30 (B)-4 wt % 50(B)-5 wt % 30 (B)-6 wt % 21 20 (B)-7 wt % 20 Antioxidant wt % 0.12 0.120.12 0.12 0.12 M100 MPa 3.2 2.1 2.7 2.0 2.4 TB MPa 3.2 9.7 11.5 9.2 2.5EB % 300 940 1065 1045 320 Hardness Duro A 77 72 80 72 81 MFR190° C.g/10 0.9 1.3 1.1 0.8 0.5 minute Flowability index I A/B 1.52 2.38 1.521.35 1.38 Extrusion ∘ ∘ ∘ ∘ Δ processability Bleeding property ∘ ∘ ∘ ∘ ∘

[0150] TABLE 7 Com- Com- Com- Com- parative parative parative parativeexample example example example Unit 4 5 6 7 (B)-1 wt % 100 (B)-2 wt %100 (B)-3 wt % 100 (B)-4 wt % 100 M100 MPa 4.0 3.8 3.2 TB MPa 9.0 17.910.5 EB % 800 750 860 Hardness Duro A 84 85 100 81 MFR190° C. g/10 5.62.3 8.0 5.4 minute Flowability index I A/B 3.44 2.69 4.53 1.57 Extrusion∘ ∘ ∘ ∘ processability Bleeding property ∘ ∘ ∘ ∘

[0151] TABLE 8 Com- Com- Com- Com- parative parative parative parativeexample example example example Unit 8 10 11 12 (C) wt % 70 (B)-1 wt %30 (B)-5 wt % 100 (B)-6 wt % 100 (B)-7 wt % 100 Antioxidant wt % 0.12M100 MPa 1.8 5.9 4.2 TB MPa 2.7 13.0 32.1 27.5 EB % 660 760 720 50Hardness Duro A 68 94 85 100 MFR190° C. g/10 6.0 5.1 5.1 minuteFlowability index I A/B 1.13 3.36 1.27 2.04 Extrusion x ∘ x ∘processability Bleeding property ∘ ∘ ∘ ∘

[0152] TABLE 9 Comparative Unit Example 14 example 9 (A)-1 wt % 60 (B)-2wt % 40 40 (C) wt % 60 Flowability index I A/B 1.34 Extrusionprocessability ∘ x

[0153] (B)-1: Ethylene-methyl methacrylate copolymer resin (methylmethacrylate content: 25 wt %, MFR 190° C.=5.6 under a load of 2.16 kg)

[0154] (B)-2: Ethylene-vinyl acetate copolymer resin (vinyl acetatecontent: 26 wt %, MFR 190° C.=2.3 under a load of 2.16 kg)

[0155] (B)-3: Random polypropylene (MFR 230° C.=8.5 under a load of 2.16kg)

[0156] (B)-4: Ethylene-butene-1 copolymer resin (butene-1 content: 19 wt%, density=0.882 g/cm³, MFR 190° C.=5.4 under a load of 2.16 kg)

[0157] (B)-5: Ethylene-vinyl acetate copolymer resin (vinyl acetatecontent: 10 wt %, MFR 190° C.=6.0 under a load of 2.16 kg)

[0158] (B)-6: Ethylene-hexene-1 copolymer resin (hexane-1 content: 17 wt%, density=0.885 g/cm³, MFR 190° C.=5.1 under a load of 2.16 kg)

[0159] (B)-7: High density polyethylene 230J (manufactured by IdemitsuPetrochemical Co., Ltd.)

[0160] (C): Ethylene-propylene copolymer (propylene content: 27.0 wt %,Mooney viscosity: ML₁₊₄100° C.=52, Q value in QPC measurement=1.8,tensile stress M100=1.4 Mpa, revealing a monomodal molecular weightdistribution curve)

[0161] Antioxidant: Irganox 1076 (antioxidant, manufactured by ChibaSpecialty Chemicals)

[0162] As described above, according to the present invention, there areobtained a thermoplastic elastomer composition which has excellentflexibility and processability, manifests no bleeding of lower molecularweight component, and is excellent particular in extrusionprocessability and calender processability, and an extrusion-moldedarticle obtained by extrusion-molding this thermoplastic elastomercomposition, or a calender-molded article obtained by calender-moldingthis thermoplastic elastomer composition, and an ethylene-α-olefincopolymer.

What is claimed is:
 1. A thermoplastic elastomer composition comprising5 to 95 wt % of the following (A) and 5 to 95 wt % of the following (B),wherein the flowability index I according to a test for flow propertieswith a capillary rheometer is 1.35 or more: (A) an ethylene-α-olefincopolymer having a tensile stress M₁₀₀ measured according to JIS-K-6251of 2.5 MPa or less, (B) a polyolefin-based resin having a tensile stressM₁₀₀ measured according to JIS-K-6251 of 2.5 MPa or more.
 2. Thethermoplastic elastomer composition according to claim 1, wherein (A) isan ethylene-α-olefin copolymer satisfying the following conditions (a)to (c): (a) α-olefin content is from 5 to 95 wt %, (b) Mooney viscosity:ML₁₊₄100° C. is from 5 to 70, (c) Q value (weight-average molecularchain length/number-average molecular chain length) according to GPCmeasurement is 4 or more.
 3. The thermoplastic elastomer compositionaccording to claim 2, wherein (A) satisfies the conditions (a) to (c)and the following condition (d): (d) a molecular weight distributioncurve is bimodal.
 4. The thermoplastic elastomer composition accordingto claim 3, wherein (A) satisfies the conditions (a) to (d) and thefollowing conditions (e) to (g): (e) a ratio (H=X1/X2) of high molecularweight peak height X1 to low molecular weight peak height X2 in amolecular weight distribution curve is from 2.0 to 7.0, (f) an area oflow molecular weight parts having chain lengths of 100 Å or less in amolecular weight distribution curve is 3% or less, (g) heat of fusion ofa crystal at temperature of from 50 to 100° C. is 5 mJ/mg or more whenmeasured by a differential scanning calorimeter (DSC).
 5. Thethermoplastic elastomer composition according to claim 4, wherein (A)has an α-olefin content of from 20 to 40 wt % and has a Mooneyviscosity: ML₁₊₄100° C. of from 15 to
 70. 6. An extrusion molded articleobtained by extrusion molding the thermoplastic elastomer compositionaccording to claim
 1. 7. A hose obtained from the molded articleaccording to claim
 6. 8. A tube obtained from the molded articleaccording to claim
 6. 9. A gasket obtained from the molded articleaccording to claim
 6. 10. A packing obtained from the molded articleaccording to claim
 6. 11. A calender molded article obtained by calendermolding the thermoplastic elastomer composition according to claim 1.12. An ethylene-α-olefin copolymer which comprises ethylene and anα-olefin having 3 to 8 carbon atoms, wherein the copolymer has anα-olefin content of from 20 to 40 wt %, has a Mooney viscosity:ML₁₊₄100° C. of from 15 to 70, and satisfies the conditions (c) to (g)according to claim
 4. 13. The ethylene-α-olefin copolymer according toclaim 12, wherein the α-olefin content is from 25 to 40 wt %.
 14. Apellet made of the ethylene-α-olefin copolymer according to claim 12.15. An extrusion molded article obtained by extrusion molding of theethylene-α-olefin copolymer according to claim
 12. 16. A hose obtainedfrom the molded article according to claim
 15. 17. A tube obtained fromthe molded article according to claim
 15. 18. A gasket obtained from themolded article according to claim
 15. 19. A packing obtained from themolded article according to claim
 15. 20. A calender molded articleobtained by calender molding the thermoplastic elastomer compositionaccording to claim 12.